DESCRIPTION (Applicant's Abstract): A variable compliance chamber (VCC) is proposed that will maintain near normal pulmonary input impedance during the treatment of pulmonary disease. Pulmonary impedance is related to the total work (steady and pulsatile) that the right heart must pump against, and it is altered (primarily in the form of decreased compliance) in pulmonary disease and in the implantation of oxygenation assist devices; this increase in work can lead to right-heart failure. A VCC will be developed that can be attached to the right-heart or combined with an implantable artificial lung to decrease the impedance seen by the right ventricle. An important application of the VCC will be to allow bridge-to-transplant or recovery treatment of patients suffering from primary and secondary pulmonary hypertension. Phase I will utilize computational techniques and bench-top experiments to allow rapid development of the VCC and thorough characterization. At the completion of phase I, a working prototype will be constructed and extensive bench-top studies will be performed to verify the ability of the VCC to decrease the pulmonary impedance spectrum, and thus decrease load on the right-heart, in the application of an oxygenation assist device. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE